Instrument for measuring the tension and the sounding length of strings.



H. WBNZEL-SGHMIDT.

INSTRUMENT FOR MEASURING THE TENSION AND THE SOUNDING LENGTH OF STRINGS.

APPLICATION FILED OUT. 7, 1912.

1,113,390, Patented 00t.13,1914.

- UNITED STATES PATENT OFFICE.

HERMANN WTENZEL-SCHMIDT, OF UNIOINPORT, NEW YORK.

INSTRUMENT roe MEASURING THE TENs'IoN AND THE SOUNDING LENGTH or a sTnrNGs.

' Specification of Letters iatent.

Patented Oct. 13, 1914.

Application fild October 7, 1912. Serial No. 724,488.

determining the tension of piano strings of an length and at any pitch.- I

Vith this object in view my invention consists of a grand-piano-like frame work to which are attached a number of piano strings, one end of which is secured to a spring balance and the other end to atuning-pin. By means of the ad ustable 1nd1- vidual bridges, the scale draftsman is able to determine the exact length of string that will produce the required tonal and tensional results.

In the accompanying drawing in which similar reference letters denote corresponding parts Figure 1 is a more or less diagrammatic plan view-of my instrument and Fig. 2 an enlarged cross section thereof on line 22 of Fig. 1.

a denotes a grand piano-like resonant board or plate of the instrument. Along the curved side a of said plate a a correspondingly-curved upwardly projecting base bar I; of substantially square cross section is fixed and along the remaining three straight edges a a and a upwardly projecting flanges a, a and of are provided. Fixed on said bar I) by screws cor in any other suitable manner are a series of spring balances d of any suitable construction such as used for weighing meat or the like.

In the present embodiment of my invention I have shown each balance to comprise a cylindrical receptacle 6 in which the hook f carrying member 9 is movably attached by means of the spring h. The said member carries a pointer or finger i which projects outwardly through a longitudinal recess 7' made in the circumference of the cylinder e and indicates on a longitudinal balance k in pounds or other measures the tensionexerted on the member 9. The cylinder e is suitably and removably mounted in the casing Z which as heretofore mentioned is fixed to the bar I) b the screws 0.

The number of balances at comprised in the series corresponds with that of the strings for the different notes of the stringed instrument, 2'. e. there is one for each string.

Fastened in a reinforced or enlarged part of the board or plate a arranged alongside the straight side a there is a threaded pin m serving as a tuning pin for each string,

which pins are arranged in a line extending in a slant transversely to the plate a and corresponding to that in which the pins are arranged in the stringed instrument for which the strings are designed. In a second substantially parallel line and at a short distance away from the pins m are arranged agrafi'es n for the corresponding strings. The sounding board or plate a is also pro vided with a series of longitudinal slots 0 each arranged between the corresponding scale (1 and the agraifes n. Each slot is adapted to receive a bridge 29 which is adjpstably mounted therein and is capable of eing fixed in any of the different positions it may be moved to by means of a thumb nut 19' or the like. The slots 0 vary in length a'ccordin to the string desired to be determined by t is instrument.

By screwing the pin m in or out the board a the string 1' is caused to wind off or on said pin tensioning accordingly the spring h which tension is indicated on the scale is bythe pointer 11. By the adjustment of the bridge 72 in the slot 0 the length measured between the adjusted position of the bridge and the agrafi'e n is ascertained. Thus after the proper adjustment of the bridge 1) or the screw pin m or of both the'required tonal and tensional results will be obtained. The

agraife n. and the bridge p and the tension of the string 7- that are determined, on one hand by reading ofi the scale k and on the other hand by measuring the distance be-' j istable pin and at the opposite end to the 7 corresponding spring-balance, anagrafie for each string anda series of bridges adjustably' molinted in said board one for each string. P

In testimony whereof I afiix my signature in presence of two witnesses.

' HERMANN WENZEL-SCHMIDT.

Witnesseei JAMES H. Goeom,

Max D. ORCHMANN. 

